Protected metal tube and the like



J. F. HARTHAN AND F. VON BICHOWSKY.

PROTECTED METAL TUBE AND THE LIKE.

APPLICATION FILED MAY I2, I9l9.

1,368,395, Patented Feb. 15, 1 921.

INVENTORS John T. Harthan BY fbordVon Bichowskg ATTORNEYS Q UNITED STATES PATENT OFFICE.

JOHN F. HARTHAN AND FOORD VON BICHOWSKY, OF POMONA, CALIFORNIA,

PROTECTED METAL TUBE AND THE LIKE.

Specification of Letters Patent.

Patented Feb. 15, 1921.

Application filed May 12, 1919. Serial No. 296,686.

To all whom it may concern: Be it known that we, JOHN F. HARTHA and Foom) VoN BIoHowsKY, citizens of Russia and of the United States, respectively, residing at Pomona, in the county of Los Angeles and State of California, have invented new and useful improvements in Protected Metal Tubes and the like, of

which the following is a specification.

Our invention relates to protected metal tubes and the like.

In many industrial processes metal tubes are subjected to high temperatures; for instance, in the synthetic production of ammonia catalytic material is placed in metal tubes and the same are subjected to a temperature of 1800 F. Such high temperatures have a corroding effect upon bare metals, especially those metals that are easily oxidizable at high temperatures. Furthermore, the flames or hot gases derived from the fuel used for heating the metal tubes usually intensify the corroding action. In time the oxidation causes the tube to disintegrate, and for this reason it is necessary to provide tubes made as permanent as possible. The ordinary metal tubes,

such as mild steel, used in the syntheticproduction of ammonia and subjected to 1800 F., last only ashort time, and require frequent renewal. The attending labor and expense of'such renewal is excessive It is an object of our invention to protect metal tubes by a simple method, and to produce a metal tube which will withstand the action of flames and high temperatures for a long time, the protective means beingrenewable at slight expense and trouble.

Our invention consists in the arrangement and construction of parts hereinafter described and claimed.

In the accompanying drawing which forms a part of this specification, we have illustrated a metal tube embodying our invention, and in which Figure 1 is a perspective view of a furnace with parts broken away showing our metal tubes in use.

Fig. 2-is a perspective view of a metal tube made in accordance with our invention, showing parts broken away to disclose the construction thereof.

Referring to the drawings, 10 indicates a furnace of any desired construction, in which the metal tube 11 containing the material to be treated is disposed. The metal tube 11 may be made of any suitable metal, usually mild steel, and the same is surrounded with a wire screen 12. The wire screen is folded about the pipe, the ends overlapping as at 13, and held in place by wires 14. The adjacent section of the screen preferably overlaps the first section as at 15. The wire screen is preferably made of iron or nickel, or their alloys, and has a mesh of about sixteen divisions more or less to the linear inch.

The wire screen 12 serves as an anchoring means for the plaster or coating 16, which we apply with a brush, the plaster adhering to the tube 11 and being firmly held in place by the wire screen.

The plaster is made of china clay or fire clay, or similar refractory material. A small quantity of a mineral fiber, such as asbestos, may be mixed therewith. The material is mixed with water glass, molasses, or the like, until it forms a soft paste.

The coating 16 is allowed to dry slowly in the open air.

Metal tubes, protected as described, rc-, sist the action of flames and high temperatures exceedingly well up to nearly the melting point of the screen material. If, in use, part of the coating is burnt off, it can easily be restored by brushing the injured part with the paste.

Various changes may be made by those skilled in the-art without departing from the spirit of our invention as claimed.

We claim:

1 In combination with a metal reaction tube, wire screen sections surrounding said \tube, the ends of said sections overlapping each other, and a refractory coating adhering to said tube in which coating said screen is embedded.

2. In combination with a metal reaction tube, wire screen sections surrounding said 

